What is a Term in WordPress?

Terms are the items inside a taxonomy, the system WordPress uses to group related posts. Think of the taxonomy as the parent grouping and each term as one entry filed under it. WordPress.org’s documentation describes taxonomies as the “parent” and terms as the “children.”

Terms group similar posts so related content is easier to find, and a single post can carry terms from several taxonomies. On a food blog, for example, a post can be assigned the terms Baking and Recipes from a Cooking taxonomy, plus Chocolate and Cake from a separate Desserts taxonomy.

Terms vs. taxonomies, categories, and tags

Every category and tag on your site is a term. Categories and Tags are the two taxonomies WordPress includes by default, so they’re the terms you’ve been using all along. Here’s how the pieces fit together:

• Taxonomy: the grouping system itself. WordPress ships with Categories and Tags, and themes or plugins can register more.
• Term: one item inside a taxonomy, with its own name and slug, plus an archive page when its taxonomy is public and queryable.
• Category or tag: a term that belongs to one of the two built-in taxonomies. A Desserts category and a chocolate tag are both terms.

Parent and child terms

Terms can nest, but only inside a hierarchical taxonomy. In WordPress, “hierarchical” has a narrow technical meaning: it describes whether the terms within a taxonomy can have parent and child terms, not the relationship between a taxonomy and its items. Categories are hierarchical, so a Desserts category can hold a Cakes subcategory, and visitors who click the parent category’s link see posts from it and all its children. Tags are flat: every tag sits at the same level. Developers set this behavior when registering a custom taxonomy with register_taxonomy(), whose hierarchical argument defaults to false.

Creating and managing terms

You don’t need code to create terms. For the built-in taxonomies, go to Posts > Categories or Posts > Tags in the WordPress dashboard to add, rename, or delete terms, or add them from the sidebar of the post editor while you write. Custom taxonomies that register an admin UI appear as a submenu of the post type they’re attached to. Developers can also create terms programmatically with the wp_insert_term() function.

One habit to avoid: creating a new term for every small variation. Near-duplicates like Recipes, Recipe, and My Recipes split the same posts across three thin archive pages and fragment your navigation. Reuse an existing term when one fits, and periodically merge or delete terms that only cover one or two posts.

Term archive pages

For public taxonomies like categories and tags, clicking a term takes visitors to a term archive page that lists every post assigned that term. WordPress builds the archive’s URL from the term’s slug, the URL-friendly version of its name, so a Desserts category typically lives at example.com/category/desserts/. Custom taxonomies can skip all of this: the public, publicly_queryable, and rewrite arguments of register_taxonomy() let developers register a taxonomy with no front-end archive at all.